What Happens to Gut Microbes After a Long Stay in ICU?

Sad, but not surprising results. It highlights the damage repeated courses of antibiotics, and even illness, do to gut microbial communities. The researchers write that during a prolonged stay in ICU they found the emergence of "ultra-low-density communities" (only 1 to 4 bacteria species) in patients. From Science Daily:

Researchers at the University of Chicago have shown that after a long stay in the Intensive Care Unit (ICU) only a handful of pathogenic microbe species remain behind in patients' intestines. The team tested these remaining pathogens and discovered that some can become deadly when provoked by conditions that mimic the body's stress response to illness.

"Our hypothesis has always been that the gut microflora in these patients are very abnormal, and these could be the culprits that lead to sepsis," he says. The current study supports this idea. Alverdy and Olga Zaborina, a microbiologist, wanted to know what happens to the gut microbes of ICU patients, who receive repeated courses of multiple antibiotics to ward off infections.

They found that patients with stays longer than a month had only one to four types of microbes in their gut, as measured from fecal samples -- compared to about 40 different types found in healthy volunteers.

Four of these patients had gut microbe communities with just two members-- an infectious Candida yeast strain and a pathogenic bacterial strain, such as Enterococcus faecium or Staphylococcus aureus and other bugs associated with hospital-associated infections. Not surprisingly, almost all of the pathogenic bacteria in these patients were antibiotic resistant.